Cadmium sulfide photo-cell



Oct- 22,1963 H. E'. STANLEY' I3,108,021

v GADMIUM sULFInE- PHoTo-'cEpL' Filed June 12", `196:1]5

United States Patent O M 3,168,021 CADMIUM SULFIDE PHT-CELL Howard E. Stanley, Los Angeles, Calif., assignor to International Rectifier Corporation, El Segundo, Calif., a corporation of California Filed June 12, 1961, Ser. No. 116,472 6 Claims. (Cl. 117-212) My invention relates to cadmium sulfide cells and more specifically relates to a novel method of manufacturing a cadmium sulfide photo-cell.

Cadmium sulfide photo-cells are well known to the art wherein an insulating surface is coated with cadmium sulfide and a pair of electro-des are applied to the cadmium sulfide layer in such a man-ner that the electrodes are separated from one another by a short distance over a large area. Tlhis is normally achieved by causing the exposed cadmium sulfide surface to travel a tortuous path.

Because of theV complex configuration of the electrodes required to serve this function, the application of the electrodes becomes an expensive and time consuming procedure. Moreover, it is difficult with present existing procedures to apply the electrodes where the distance through the cadmium sulfide is required to be exceedingly short.

The principle of the invention is to perform the backing material which receives the cadmium sulfide layer so that the conductive electrodes can be stamped or rolled on the surface of the device with the portions of the surface which are to receive conductive material being raised and are therefore the only portions which are coated. More specifically, a backing material may have a groove etched therein which has a configuration of the cadmium sulfide region which is interposed between the electrodes. Thereafter, the complete backing material is fir-st coated with cadmium sulfide and the unit is thereafter stamped on an ink pad which has a silver conducting paint therein or is rolled with a roller carrying a silver conducting paint. The silver will be applied only to the raised sections when either of these typical methods are used so that the two electrodes are inherently coated on the cadmium sulfide surface and depressed areas will not receive the conductive medium.

Accordingly, a primary object of this invention is to provide a novel method of manufacture for cadmium sulfide photo-cells.

A further object of this invention is to provide a novel method for applying the conductive electrodes to a cadmium sulde photo-cell.

A further object of the invention is to provide a novel preformed backing material for cadmium sulfide photo# cells which permits the simplified application of conductive electrodes to the device.

These `and other objects of the invention become apparent from the following description which is taken in connection with the drawing in which:

FIGURE 1 shows a perspective view of an insulating backing material preformed in accordance with the novel invention.

FIGURE 2 is a side cross-sectional view of the insulated backing structure of FIGURE 1 when taken across line 2-2 of FIGURE l.

FIGURE 43 illustrates the insulating backing material of FIGURES f1 and 2 after the coating of a cadmium sulfide layer and the application of electrodes thereto.

Referring first to FIGURES 1 'and 2, the novel cell of the invention includes a backing material 1f) of some insulation material. By way of example, the body 1li, may be formed of a glass or ceramic insulation material. It has been found that a ceramic serves the function to be described in a satisfactory manner.

3, l hl Patented @ein 22, 1963 ICC A tortuous channel 11 is formed in the upper surface of base 1t) as illustrated in FIGURES 1 and 2 where the channel takes a path to Abe defined by the portions of the cadmium sulfide layer which is exposed by the electrodes of the device. Thus in FIGURE l the tortuous path is seen to be typical of that used in most cadmium sulfide devices. The depth of channel 111 is selected so that the subsequent application of the cadmium sulfide layer will still leave raised sections which can receive a conductive medium.

The body 1li then has a cadmium sulfide mix applied thereto and is then fired in an oven for example at 650 degrees centigrade so that a cadmium sulfide layer 12, shown in FIGURE 3 is applied over at least the upper surface of base 1li as shown. The cadmium sulfide layer 12 can of course be applied to the upper surface of body 10 in any manner well known to those skilled in the art.

The raised surface portions of the base exactly define the configuration of the device electrodes which are later formed by applying a conductive medium to the surface off the device. The conductive medium which is applied to raised surface 1%3, will define a first electrode while the conductive medium applied to raised surface 14 will define a second electrode. In cross-section, the conductive media are shown in FIGURE 3 as conductive portions 15, 16, 17, 18, 19, 20 and 2l. It will be noted that the conductive medium does not extend into the groove 11.

The application of the conductive medium shown in FIGURE 3 can, in accordance with the invention, be performed by use of a roller which carries a silver conducting paint or by stamping the unit on an ink pad which contains a silver conducting paint.

In the foregoing, I have described my invention only in connection with preferred embodiments thereof. Many variations and modifications of the principles of my invention within the scope of the description herein are obvious. Accordingly, I prefer tobe bound not by the specific disclosure herein, but only by the appending claims.

I claim:

l. The method of manufacture of a photoccll; said method comprising the formation of a groove in a surface of a sheet of insulation material to divide said sheet into a first and second section separated by said groove, coating said surface Iof said sheet of insulation material with a photosensitive material, said photosensitive material forming a layer on the interior of said groove and on at least the portions of said surface adjacent said groove, and applying a conductive medium to said surface von either side of said groove, said conductive medium forming a layer on said first and second sections and not coating the interior of said groove.

2. The method of manufacture of -a cadmium sulfide photo-cell; said method comprising the formation of a tortuous groove in a sheet of insulation material to divide said sheet into a first and second section separated by said groove, coating the interior of said groove and at least a portion of said surface adjacent thereto of said sheet of insulation material with a cadmium sulfide material, and applying a conductive medium to said cadmium sulfide surface on either side of said gooi/e, said conductive medium forming a layer on said first and second sections :and not coating the cadmium sulfide surfaces in the interior of said groove.

3. The method of manufacture of a cadmium sulfide photo-cell; said method comprising the formation of a groove in a surface of a sheet of insulation material to divide said surface into a first and second section,v coating said sheet of insulation material with cadmium sulfide, said cadmium sulfide forming a layer on the interior of said groove and over substantially all of said surface, and applying a conductive medium to said cadmium sulfide surface on either side of said groove only to define a layer of said conductive medium on said first and second sections respectively.

4. The method of manufacture of a cadmium sulfide cell comprising the steps of preforming the surface of an insulating base to have a depressed section following the path of cadmium sulfide to be interposed between a first and second electrode, applying a layer oftcadmium sulfide to said depressed section and to arcas adjacent said depressed section, and thereafter applying a conducting medium to portions of said surface raised above said depressed section to define said first and second electrodes, said conducting medium not coating the layer of cadmium sulfide formed in said depressed section of said surface.

5. The method of manufacture of a cadmium sulfide photocell comprising:

(n) forming a tortuous groove in a surface of a sheet of insulation material to divide said surface into first and second sections separated by said groove,

(b) coating said sheet with cadmium sulfide to form a layer on the interior surfaces of said groove and on said first and second sections of said sheet,

(c) moving a roller impregnated with a silvercontaining conductive material over the sheet of insulation material to apply said silver-containing conductive material over the cadmium sulfide layer on said first and second sections of said sheet and yet not coat the cadmium sulfide layer in the interior of said groove, said silver-containing conductive material defining first and second conductive electrodes aligned with said first and second sections.

6. The method of manufacture of a cadmium sulfide photocell comprising:

(a) forming a tortuous groove in a surface of a sheet of insulation material to divide said surface into first and second sections separated by said groove,

(b) coating said sheet with cadmium sulfide to form a layer on the interior sur-faces of said groove and on said first and second sections of said sheet,

(c) stamping the sheet of insulation material with a pad impregnated With a silver-containing conductive material to apply said silver-containing conductive material overthe cadmium sulfide layer on said first and second sections of said sheet and yet not coat the cadmium sulfide layer in the interior of said groove, said silver-containing conductive material defining first and second conductive electrodes aligned with said first and second sections.

References Cited in the file of this patent UNITED STATES PATENTS 2,014,650 Heintz Sept. 17, 1935 2,879,182 Pakswer et al. Mar. 24, 1959 2,999,249 Nicoll Sept. 5, 1961 FOREIGN PATENTS `1,236,512 France June 13, 1960 

1. THE METHOD OF MANFACTURE OF A PHOTO-CELL; SAID METHOD COMPRISING THE FORMATION OF A GROOVE IN A SURFACE OF A SHEET OF INSULATION MATERIAL TO DIVIDE SAID SHEET INTO A FIRST AND SECOND SECTION SEPARATED BY SAID GROOVE, COATING SAID SURFACE OF SAISD SHEET OF INSULATION MATERIAL WITH A PHOTOSENSITIVE MATERIAL, SAID PHOTOSENSITIVE MATERIAL FORMING A LAYER ON THE INTERIOR OF SIAD GROOVE AND ON AT LEAST THE PORTIONS OF SAID SURFACE ADJACENT SAID GROOVE, AND APPLYING A CONDUCTIVE MEDIUM TO SAID SURFACE ON EITHER SIDE OF SAID GROOVE, SAID CONDUCTIVE MEDIUM FORMING A LAYER ON SAID FIRST AND SECOND SECTIONS AND NOT COATING THE INTERIOR OF SAID GROOVE. 